The present invention relates to a color filter for a color imaging device and a method for making the same and, more particularly, to an improvement in a color filter array structure integrally formed on a surface of a solid-state image sensor so as to improve the utilization efficiency of incident light.
A single chip color camera is receiving a great deal of attention wherein a color filter array is formed on a surface of a solid-state image sensor. The color filter array is directly formed on the surface of the solid-state image sensor in the following manner. An emulsion is applied to the surface of the solid-state image sensor, and part of the emulsion is selectively treated with a dye. The dyed portion serves as a color filter portion which absorbs light of a specific wavelength. The above process is repeated several times to prepared a checkerboard like array of color filter portions.
A solid-state image sensor used in conjunction with the filter array comprises a photodiode array as a photosensitive section, and a transfer section for transferring a signal photoelectrically transduced by a photodiode of the array. The total area of the photosensitive section comprising the photodiode array is 25 to 30% of the total surface area of the solid-state image sensor. Therefore, only a small amount of the light incident on the surface of the solid-state image sensor through a image pickup lens is subjected to the photoelectric transducing operation. 70 to 75% of the total amount of incident light does not contribute to the photoelectric transducing operation and is wasted.